“We used GRT to carry out the service of our Viessmann boiler. Communications were excellent and perform the work in a timely manner. Price as expected and found tone very professional. Will use again ...

"Viessmann boiler installation. Excellent work, tidy, on time and professional. I would recommend this company to anyone. Very pleased." - Mr Estall

"David was the one person that actually delivered on his promises. His workmanship and knowledge were excellent."- Mr Green